GBLs. The beauty of this method lies in exploring the structure in
its innate form, without having to attach extrinsic fluorophores that
could potentially lead to conformational changes in the protein.
The ligand binding studies in this protocol are performed with
two chemically synthesized GBLs, Cp1 and Cp2 (Fig.3). Cp1
(3-hydroxymethylbutanolide) is a basic butyrolactone moiety
whereas Cp2 (2-(1^0 -hydroxyoctyl)-3-hydroxymethylbutanolide)
has an additional aliphatic chain with eight carbon atoms. If a
library ofγ-butyrolactones and their variants is available, then an
array of these ligands (Fig.3) and variousγ-butyrolactone receptors
can be screened rapidly in a fluorescence microplate reader setup.
Thus large-scale screening with small quantities of ligands can be
undertaken efficiently with microplate reader systems.Fig. 2Sequence alignment of GBL family of receptor proteins. The conserved tryptophan is shown inred
Fig. 3γ-Butyrolactones and their variants
134 Jessy Mariam and Ruchi Anand